The long-term objective of the project is to develop, clinically test and commercialize the novel insertable x-ray device developed by AXT. This portable x-ray needle, is intended for delivery of low energy, high RBE radiation directly to the tumour beds and is considered to be a viable alternative to radioactive sources used in the High Dose Rate Brachytherapy. The main advantages of AXT's x-ray device include such features as a controllable on/off mode, exceptional stability of the produced radiation, adjustable dose rate, and the ability to function in a conventional operating room with almost no radiological exposure to staff. The initial application of the device is the accelerated partial breast irradiation. The main goal of the Phase II project is to design, build and test a new model of the x-ray needle with an elevated dose rate of the produced radiation (1Gy/min at 10mm in tissue). Other goals include the development of low-energy (8-18 keV) dosimetry protocols and a treatment planning approach involving the x-ray needle. To achieve the stated goals the following specific aims of the project have to be fulfilled. The specific aims of the project are: (i) design, build and test an ellipsoidal and Johansson type concentrators fabricated from a Highly Oriented Pyrolytic Graphite, (2) incorporate the concentrators into an optical collimator, (3) integrate the collimators into an x-ray needle, (4) perform measurements of dose rate and dose rate spatial distribution (isodose), (5) design and build a balloon applicator and test it jointed with an x-ray needle, (6) install an x-ray needle device in a conventional movable arm. The potential market for such device is significant. It is estimated that more than 275,000 women in the United States are annually diagnosed with breast cancer and about 50% of them are treated with radiotherapy. Development of the new model of AXT's insertable x-ray device offers hope and promise for cure and improvement to the quality of life for many affected people. [unreadable] [unreadable] [unreadable]